Brightness and Volume not working on Samsung 65" QN800D 8K

[MHX792]

It just gets recognized as "SAMSUNG" but brightness and volume do not work. Also, 8K resolution can't be set, i.e. only 4K resolution is shown. But I don't know if this is related to BetterDisplay, as the macOS Settings app also only scales up to 4K. Note that my HDMI cable supports 8K (BENFEI 8K USB C to HDMI).

Any help is appreciated! Thank you

[waydabber]

What Mac do you have? If you have a modern Mac, it should support 8K (make sure you have "Input Signal Plus" enabled for the port in the Samsung TV menu!). Brightness control won't work with Samsung TVs (these do not support DDC or brightness control over the network, like LG TVs do), you can control the volume (steps only) by adding a Samsung controller for the display and configuring network control. This will also give you a Samsung TV remote under the Device Control menu.